GRHL2 and autosomal dominant nonsyndromic hearing loss 28: GRHL2 is also present in the cochlear duct,14 and mutations in human GRHL2 have been found in progressive autosomal-dominant hearing loss (DFNA28 [MIM 608641]),15,16 and other polymorphic sequence variants in GRHL2 have been implicated in age-related hearing impairment and noise-induced hearing loss.17–19 To date, however, the role of GRHL2 in skin biology has not been well established.